There’s a vague notion that turning Bluetooth off is one way to meaningfully increase a phone’s battery life. Assuming this is true, I wanted to upper bound how much of Bluetooth’s power consumption could be attributed to the raw transmission power, as opposed to the incidental power consumption of the hardware/software itself.

Here are the battery specs of a representative modern smartphone, the Nexus 5X:

Bluetooth Low Energy’s (BLE) maximum transmission power (page 16) is 10mW. With zero incidental power consumption, here’s how long it would take to drain the Nexus 5X battery based on continuous Bluetooth LE transmission power alone: 10,800 / 10 = 1,080 hours = 45 days.

In summary, Bluetooth’s power consumption on a modern smartphone is hardly attributable to raw transmission power alone.